If you’re looking to go back in barroom time, the Skip Castro Band will take you there. These longtime veterans of shot-and-a-beer musicality have been doling out their user-friendly mix of boogie, swing and rock ’n’ roll up and down the Eastern Seaboard since the late 1970s — with a reputation built on the strength of their live performances. I’ve seen the band at least twice in every decade since the 1980s and not once did it fail to deliver the goods. Trends and fads come and go, but the Skip Castro Band remains the quintessential bar band of this or any era. The group plays Saturday, May 21, at the Tin Pan. Doors open at 8 p.m. $20-$25. tinpanrva.com.